1) Field of the Invention
The present invention relates to technology for making it easy to identify an original and a duplicate of the original by printing on a paper together with the printing data ground-tint patterns that are not noticeable in the original but are manifested in the duplicate when the original is duplicated.
2) Description of the Related Art
In recent years, a duplicate can be made with high picture quality because of the advance in the copying technique so that the duplicate that is almost same as the original can be obtained. However, on the other hand, there are problems of falsely using duplicates, and a technique that can identify the original from the duplicate has been waited.
As a method for identifying the original from the duplicate, hitherto, special-purpose paper in which ground tints containing seemingly inconspicuous hidden character strings are printed in advance and the hidden character strings are manifested when it is duplicated.
FIG. 13 is an example of ground tint containing hidden character strings. The character portion is formed by ground-tint copy-extinctive patterns and other portion by ground-tint copy-surviving patterns. The ground-tint copy-extinctive patterns are composed of dots smaller than the minimum dots of the reading resolution of a copying machine, while the ground-tint copy-surviving patterns are composed of dots larger than the minimum dot of the reading resolution of the copying machine. Both patterns are set to a similar dot occupation ratio per area, that is, to a similar density, and as a result, the paper has properties difficult to visibly identify the difference even when both patterns are mixed. However, in duplicates, dots of the ground-tint copy-surviving pattern area only are printed and the ground-tint extinctive pattern area is outlined, and as a result, copy suppression character strings by ground-tint copy-extinctive pattern are manifested on duplicates.
Japanese Patent Application Laid-Open Publication No. 2001-238075 proposes that two kinds of dither patterns with varying profiles with same density are used for the back area and the character area, respectively, by the copy prohibition pattern generator, and even when the print result, that is, the original document, is seen, it is impossible to identify the hidden character strings but when the original is optically read by scanner and duplicated by copying machines such as duplicators, etc. which reproduce the original on the form, copy prohibition patterns with hidden character strings formed are generated so that the hidden character strings can be identified.
Japanese Patent Application Laid-Open Publication Nos. H9-164739 and 2001-324989 disclose related arts.
Thus, as a method for identifying the original and the duplicate, the use of special-purpose form with ground-tint patterns already printed can be considered, but the form (paper) cost is high and should the form itself be stolen, there is a possibility that forgery is committed by the use of the form itself, and antitheft measures must be provided, causing problems in usability.
In addition, even when special-purpose form with ground-tint patterns printed is used, in the system of simultaneously printing the printing data and ground-tint pattern data as in the technique disclosed in Japanese Patent Application Laid-Open Publication No. 2001-238075, in recent years, the reading accuracy by scanner has been improved and it has become possible to duplicate the data with ground tint included as it is.
Now, as an example of documents whose original only is effective, there is a directive for prescribing drugs, that is, prescription which is issued by a physician to a patient. In recent years, prescription preparation programs for automatically preparing the prescription by the use of computer have been developed and it has become possible to easily prepare a prescription. That is, when a prescription is prepared, a prescription preparation program is activated, the prescription is prepared by entering the prescription data such as drug and the dose specified by the physician and patient name, etc. and allowing a printer to execute printing. And the prepared prescription has a seal affixed and handed to the patient, and the patient receives the drug specified by the doctor by submitting the prescription to a pharmacy.
In case of the prescription, there are in-hospital prescription addressed to pharmacies inside the hospital facilities and extramural prescription addressed to the pharmacies. In the case of the in-hospital prescription, the physician issues an in-house prescription to the patient and at the same time, the electronic duplicate is issued to the pharmacy inside the hospital facilities, and dispensing is begun without waiting for the arrival of the original in-house prescription of the patient. In the case of the extramural prescription addressed to the pharmacies, the patient him/herself must bring the extramural prescription to a pharmacy and receive the formulated drug. When the extramural prescription is brought, as shown in FIG. 14, there are two cases in which the patient brings the prescription to the pharmacy where the patient generally goes (hereinafter, “always-used pharmacy”) and in which the patient brings the prescription to a general pharmacy other than his/her always-used pharmacy as shown in FIG. 15.
In a system in which the patient him/herself brings the extramural prescription to a pharmacy, and the dispensing operation begins after the prescription is received from the patient, a sick patient must be kept waited for a specified time at the pharmacy. Therefore, in order to minimize such waiting time, as in the case of the prescription shown in FIG. 14, it is a common practice to provide services to send the extramural prescription by fax to the always-used pharmacy from the extramural prescription issuing institution on the request of the patient, and enable the pharmacy to begin dispensing without arrival of the original prescription as in the case of the in-house prescription.
However, because legally speaking, the extramural prescription should not be issued for a specific pharmacy, as in the case of FIG. 15, even a pharmacy which is not the always-used pharmacy must dispense the content of the prescription if the patient or the person concerned who is entrusted by the patient brings the extramural prescription to the pharmacy, and the extramural prescription is generally effective for 4 days including the issuing date.
Consequently, while there is extremely little possibility of ill-willed duplication of the prescription by the patient and the person concerned with the patient with respect to the issuance of the in-hospital prescription, in the case of the extramural prescription, no one can deny the possibility for the patient or the person concerned with the patient to prepare duplicates of the original extramural prescription by the use of color copying machine for the purpose of ill-willed acquisition of drugs before bringing the original extramural prescription to a pharmacy, and to submit the duplicates to the pharmacies. In addition, because a pharmacy has a duty to dispense the content of the extramural prescription, the pharmacy may dispense the drug in compliance with the content of the illegal extramural prescription if it is extremely difficult to determine whether the extramural prescription submitted is an ill-willed illegal duplicate or an original. Actually, there are examples of patients who made a plurality of duplicates of extramural prescriptions and attempted to obtain drugs from a plurality of pharmacies.
In the drugs prescribed by medical institutions, there are cases in which drugs whose abuse is legally prohibited, such as narcotics, psychotropic substances, etc. are included, and allowing anyone to illegally acquire such drugs not only poses a high risk but also results in problems that might endanger people's life due to buying and selling of illegally acquired drugs, their abuse, etc. However, preparing prescriptions by the use of special-purpose watermarked forms increases cost, and even when the cost is suppressed by printing the printing data including ground tints on plain paper, if duplicates are purposely prepared, duplication is available with the ground tints included, and it is the current situation that illegal duplicates are let to pass.